At the start of every new year, people the world over make resolutions to better themselves, with fitness, health, money, and career goals at the forefront of our minds. But what about your poor, neglected PC? Couldn't it use, at the very least, a few resolutions toward better health and fitness?

Today, I've compiled a list of 7 PC resolutions - those nagging PC activities you should engage in more often but don't - to help you and your computer start off the new year on the right foot. From defragging and backing up your hard drive to organizing your documents, this is a roundup of best practices and automation tools straight from the Lifehacker vault.

Note: The following PC resolutions apply to both Windows PCs and Macs (except for the bit on hard drive defragmentation), so when applicable I've tried to include Mac and Windows solutions. Most of the required software is freeware, so all you need to follow any of these tips is a little bit of time and resolve.

1. Regularly back up your hard drive: If there's one thing that nags most computer users in the "I-know-I-should-but-I-don't" way, it's hard drive back ups. We've all been there: as long as your hard drive keeps on spinning, it's easy to ignore the whole back up thing - until the Grim Reaper comes knocking at your door in the form of the dreaded BSoD, that is.

2. Set up a self-repairing hard drive: Windows only: Most Windows users have heard that they should defragment their hard drives on a semi-regular basis, but I'd venture to guess that of the users who actually know what that means, even fewer actually do it. Why? Because, like any other preventative measure, it can seem like a pain in the ass; nobody wants to sit around watching and waiting for their hard disk to defrag.

3. Clean out your hard drive: It's easy to let your hard drive get filled up with files you neither need nor use, but it can be hard to roll up your sleeves and actually clean everything up. The messier that hard drive gets, though, the tougher it can be to find those things you actually want.

You could sit down and go through your folders one by one (and, to be honest, this isn't a bad way to go if you've got the right time), but if you don't have a few hours to spend pruning your drive, we've covered a few methods to visualize your hard drive usage on both Windows and Mac PCs. Once you've got a good visual representation of what's what on your hard drive, it becomes much easier to get rid of files you didn't even know existed.

While you're cleaning out files, you might want to set up your antivirus and spyware cleaners for scheduled sweeps if you haven't already (hopefully you have). You can also clean up a little space with the aptly named CrapCleaner. Now might also be a good time to go through your installed programs and get rid of anything you don't use.

5. Keep your hard drive clean: So your hard drive is finally free of clutter, and you've got a new system in place to keep everything organized, but... what's to say you're ever going to stick to that?

Apart from your will power (which I'm sure is excellent), there are a couple of great automation tools that can help you keep everything in its place. On Windows PCs, the free Hard drive Janitor script will monitor specified folders and clean out files older than a user-defined number of days.

On the Mac side of things, the incredible shareware app Hazel lets you monitor user-defined folders and set rules for deleting and moving files within those folders based on a very powerful filtering system (for example, you can send all MP3 files in a folder to an iTunes playlist, while deleting all .dmg files older than a week). If you're looking for a bit of Windows shareware that works similarly to Hazel, you might want to check out Cleandesk Organizer.

6. Encrypt your private data: Whether you're keeping your secret video stash hidden from the kids or you actually have sensitive data you want to hide from the prying eyes of the world at large, now's as good of a time as any to encrypt your Windows data with TrueCrypt. For a freeware Mac solution, try QuickEncrypt.

7. Securely track your passwords: While we're on the subject of privacy, there's always the matter of those pesky passwords - you know, the ones written on Post-It notes, hanging from your monitor? First, you may need to start choosing better passwords.

Already got strong passwords? Good. Windows users can securely track those passwords with KeePass. If you work on a PC but moonlight on a Mac, you can export and encrypt the password list from KeePass (if you want to have access to your KeePass list on a Mac). In general, though, the Mac's built-in Keychain app handles a lot of the duties of KeePass.

A fresh start

If you'd love to follow some of these PC resolutions on your computer, but you've got that lost-cause feeling that comes from years of neglect, maybe it's time to start over from scratch.

You may have noticed that most of our PC maintenance howto's were written by Gina, who's a model of healthy and smart PC livin'. We'd all do well to follow in her footsteps.

If you've got your own list of PC resolutions for 2007, share them in the comments.

Adam Pash is an associate editor for Lifehacker whose resolved to make '07 the year of hard drive perfection. His special feature Hack Attack appears every Tuesday on Lifehacker. Subscribe to the Hack Attack RSS feed to get new installments in your newsreader.